1. Field of the Invention
This invention relates to a novel natural red coloring matter completely without the pungent taste obtained from a hot red pepper as a raw material and to its processing method.
The terms used hereinafter in this specification have the following meaning.
(1) Coloring component oil:
A hot red pepper seed oil in which coloring (pigment) components are eluted as a effective component.
(2) Smelling substance oil:
A hot red pepper seed oil in which smelling substances are eluted as a effective component.
(3) Color value:
A color value is determined by the following measurement method.
(1) Preparation of sample solution:
About 0.2 g of a sample is exactly weighed and is completely dissolved in 250 ml of acetone (reagent: JIS first class), and 5 ml of this solution is taken out. Acetone is added to this solution to make a total volume of 100 ml.
2) The sample solution prepared above is placed into a quartz cell (thickness of a liquid layer: 10.0 mm) and absorbance (A) at a wavelength of 460 nm is measured by a spectrophotometer.
3) The result obtained above is substituted for A in the following equation to obtain the color value: EQU color value=A.times.66,000/(w.times.2).
(4) Ratio of absorbances:
Absorbances at a wavelength 454 nm and a wavelength of 470 nm are measured in the same way as described above and a ratio of absorbances is calculated according to the following equation: EQU ratio of absorbances=(absorbance at 470 nm)/(absorbance at 454 nm).
(5) The evaluation "No pungent taste" in an organoleptic test represents the level at which five panelists (two adult males and three adult females each having an ordinary sense of taste) do not feel the pungent taste at their tongue tip.
2. Description of the Prior Art
Recently, natural coloring matters have drawn an increasing attention in place of conventional synthetic coloring matters from the aspect of safety in the fields of foodstuffs and cosmetics. Among the natural coloring matters, the demand for red coloring matters tends to increase more and more.
Conventionally, red natural coloring matters are the carotenoid type pigments (comprising principally capsanthin) extracted and prepared from red peppers (primarily, paprica). A supercritical gas extraction method has drawn a specific attention as the extraction method for preparing the red coloring matter from the red peppers, because this method is free from the problem of denaturation due to a residual organic solvent and to high temperature processing at the time of extraction and can extract and isolate only the coloring component oil at a high yield. Accordingly, various supercritical gas extraction methods have been proposed to this date (e.g. U.S. Pat. No. 4,400,398 and Japanese Patent Laid-Open Publication No. 112,659/1988).
However, it has been believed very difficult to extract the coloring matter without containing any pungent taste components even by the supercritical gas extraction method. Even a trace of the pungent taste in the coloring matter will be detected by the organoleptic test. If judged as "having the pungent taste", the coloring matter can be applied to only specific foodstuffs and its application is drastically limited. Accordingly, the red peppers as the starting material for the coloring matters have predominantly been sweet red peppers such as paprica.
On the other hand, the share of the hot red peppers in the worldwide production quantity is from about 70 to 80% and the rest are the sweet red peppers, i.e. 20 to 30%. The hot red peppers, therefore, have higher stability from the aspect of the supply of the raw mateial and can be purchased for about half-price of sweet red peppers as papricas or the like. And, various processes have been proposed in order to extract and isolate the coloring component oils, which hardly contain the pungent taste components, from the hot red peppers by the supercritical gas extraction, as listed below.
1 U.S. Pat. No. 4,400,398:
This process comprises a first step of subjecting the dried and pulverized hot red pepper to a primary supercritical gas extraction under the condition of a pressure of from the critical pressure to 150 bars (from the critical pressure to 147 kgf/cm.sup.2) and a temperature of from the critical temperature to 70.degree. C., and isolating at a reduced pressure a smelling component oil (containing the pungent taste component) from the extracting solution, and a second step of subjecting the extraction residue of the first supercritical extraction to a secondary supercritical gas extraction under the condition of a pressure of from 150 to 350 bars (147 to 343 kgf/cm.sup.2) and isolating at a reduced pressure a coloring component oil from the extracting solution.
2 Japanese Patent Laid-Open Publication No. 242559/1986:
This process comprises immersing a Guinea pepper (hot red pepper) in an oil such as a corn oil, a palm oil, or the like, so as to eluate the pungent taste component and the coloring component into the oil, extracting the coloring component under a pressurized condition suitable for the extraction of a coloring component and isolating at a reduced pressure the coloring component oil from the extraction gas.
3 Japanese Patent Laid-Open Publication No. 258558/1988:
This process is fundamentally the same as the process described in item 1 above, but the primary gas extraction conditions are a pressure of from the critical pressure to 170 kgf/cm.sup.2 and a temperature of from the critical temperature to 85.degree. C. and the secondary critical gas extraction conditions are a pressure of from 170 to 500 kgf/cm.sup.2 and a temperature of from the critical temperature to 85.degree. C. Both the primary and secondary critical gas extraction conditions are shifted to a higher pressure side.
However, the results of experiments carried out by the present inventors reveal that it is very difficult to bring the coloring component oil to the level of "No pungent taste" by the evaluation of the organoleptic test by any of the processes described above. In the case of the embodiment (B) of Japanese Patent Laid-Open Publication No. 258558/1988, for example, the residual capsaicin concentration in the coloring component is 0.01% and yet the evaluation result of the organoleptic test proved to be "pungent taste".
When the coloring component oil is extracted by the supercritical gas extraction in accordance with each of the processes described above, the pressure must exceed 150 kgf/cm.sup.2. Since a ultra-high pressure above 150 kgf/cm.sup.2 is necessary from the aspect of the yield (the higher the extracting pressure, the higher becomes extraction efficiency of the coloring component oil; the extraction pressure of 450 kgf/cm.sup.2 is employed in the embodiment described above), the supercritical gas extraction apparatus must withstand the ultra-high pressure and a high level of skill is necessary for various extraction operations.
It is therefore an object of the present invention to provide a natural red coloring matter, which is evaluated as "No pungent taste" in the organoleptic test, produced from the hot red pepper oleoresins by the supercritical gas extraction.
It is another object of the present invention to provide a process for preparing a natural red coloring matter which can drastically reduce the extraction pressure in comparison with the prior art technique during the supercritical gas extraction step when the natural red coloring matters are prepared from the hot red pepper oleoresins.